Screw-type skin seal with inflatable membrane

ABSTRACT

A skin seal or trocar stabilizer with an inflatable membrane disposed inside, whereby medical instruments may be passed through the skin seal into a endoscopic work space while the inflatable membrane is inflated, thereby allowing the use of normal short conventional open surgery instruments during endoscopic procedures and during insufflation.

FIELD OF THE INVENTION

This invention relates to the field of surgical endoscopy, specificallyto improvements in skin seals and cannulas.

BACKGROUND OF THE INVENTION

Surgical endoscopy is a surgical technique of using small-diameterlong-handled tools such as graspers, forceps, scissors, retractors,dissectors and clamps specially designed to be inserted through smallincisions in the skin (or other openings in the body) to performoperations within the body. The surgeon performing the surgery oftencannot see the operation directly, and must watch the procedure on avideo monitor fed by an endoscopic camera or endoscope. Endoscopicsurgery replaces open surgery, which requires large incisions,essentially opening the body cavity completely, in order to performsurgery deep within the body. Endoscopic techniques have been used forgall stone removal, gall bladder removal, hernia repair, tumor removal,lymph node removal and appendectomy and many other operations.Endoscopic surgery is also called laparoscopic surgery, video assistedsurgery, minimally invasive surgery, and band-aid surgery, butthroughout this specification the term endoscopic surgery orlaparoscopic surgery will be used.

To illustrate the background of the inventions described below, theexample of the laparoscopic cholecystectomy, hernia repair orlymphadenectomy, as well as the operation for harvesting a blood vessel,will be used to illustrate both the old laparoscopic procedures and thenew laparoscopic procedures now possible with the new devices. In theold procedure, a working space was created in the abdomen using theprocess called pneumoperitoneum or insufflation. Insufflation is theprocess of injecting gas into the body to blow it up like a balloon,creating a chamber filled with gas. When performed on the abdomen, theperitoneum is inflated and the procedure is known as pnuemoperitoneum.The procedure can be used for inflating a space between the peritoneumand the skin to permit laparoscopic hernia repair, as illustrated inU.S. Pat. No. 5,496,345 issued to Kieturakis et al. and entitled "AnExpansible Tunneling Apparatus for Creating An Anatomic Working Space".Insufflation can be used also to inflate a tunnel shaped working spaceover a blood vessel, to facilitate blood vessel harvesting, as describedin U.S. patent applicatin Ser. No. 08/267,484 entitled "ExtraluminalBalloon Dissection Apparatus and Method" incorporated herein byreference. While the chamber is filled with gas, the surgeon insertslong slender laparoscopic tools through trocars and cannulas whichpierce the skin and provide access ports into the insufflated chamber.

For abdominal surgery such as a cholecystectomy (gall bladder removal),the insufflation is accomplished by the following procedure. An incisionis made at the lower edge of the belly button or umbilicus. The surgeonuses his fingers or a blunt dissection tool such as a blunt nosedobturator to uncover the fascia or abdominal muscles, then a largeneedle, referred to as a Verres needle is inserted into the abdomen orperitoneal cavity. The Verres needle punctures the fascia and peritoneumwhich cover the abdomen. A pressurized gas such as CO₂ is injected intothe abdomen through the needle, in effect inflating the abdomen like aballoon. After the abdomen is inflated, the Verres needle is removed.After the needle is removed, trocars and cannulas are inserted into thespace created by the insufflation. Endoscopic instruments including anendoscope or laparoscope, scissors, graspers, etc., are inserted intothe abdomen through the cannulas and manipulated to dissect tissuesurrounding the gall bladder, remove the gall bladder, and stitch theinternal wounds.

To harvest the saphenous vein using laparoscopic procedures, the surgeonmay insufflate a tunnel shaped work space over a blood vessel. Thetunnel is first created using obturators or tunneling devices orballoons inserted through small incisions along or over the saphenousvein. After the tunnel is created, the surgeon may insert skin seals andcannulas, and insufflation gas is injected through one of the trocars.While the tunnel is insufflated, the cannulas permit the surgeon toinsert laparoscopic instruments into the tunnel to perform surgery onthe saphenous vein.

The cannula used in the procedures described above is a length of rigidtube. The trocars and cannula are designed to allow laparoscopicinstruments to pass through them and prevent gas from escaping theabdomen or other insufflated work space. The cannula may have a flappervalve or a trumpet valve inside which opens to allow an endoscope orlaparosope or other instrument to pass through, and valve closes whenthe laparoscope is removed. Some trocar/cannula devices also contain aduckbill valve to assist in sealing the trocar. The cannulas aretypically about 6 inches or 15 centimeters long, and come in diametersmatching various laparoscopic devices, generally from 2 to 15 mm.

Some surgeons use bare cannulas, secured only by a tight fit with theskin and fascia. However, cannulas frequently slip out of the bodyduring use, disrupting the procedure and possibly endangering thepatient. To prevent this danger, surgeons have devised a variety ofmethods to secure the cannula to the body and prevent it from slippingout of the body. Some cannulas are provided with threaded sleeves, fixedto the cannula. Some cannulas are provided with a threaded gripper witha smooth inner bore that matches the size of the cannula, so that thecannula can slide inside the gripper as shown in FIG. 2. The gripperstabilizes the cannula so that it will not slip out of the bodyinadvertently, but can be easily slipped out when the surgeon wants. Thethreaded gripper is simply screwed into the incision in the skin. Thisoption permits the ready insertion and removal of smooth walled cannulasby sliding them in and out of the gripper. Other grippers have beenused, such as the gripper with expandable arms, the gripper withinflatable balloon on the outside, and the Hasson cannula. These devicesare illustrated in Oshinsky, et al., Laparoscopic Entry and Exit,reprinted in Urologic Laparoscopy at 91-101 (Das & Crawford ed. 1994).These devices are variously referred to as threaded skin seals, screwskin seals, skin anchors, obturators, grippers, trocar stabilizers orcannula stabilizers.

The surgeon usually needs to place several trocars and cannulas into theabdomen, and inserts as many as needed to accomplish the intendedoperation. The first cannula placed through the belly button is used toinsert a laparoscope so that the placement of other trocars and cannulascan be viewed from inside the abdomen. After several cannulas are inplace, the surgeon can view the procedure through any port, and caninsert laparoscopic scissors, cutters and graspers and other toolsthrough the cannulas in order to perform the surgery. The typicalendoscopic graspers 3 used for stitching inside the abdomen are shown,deployed inside the cannulas, in FIG. 2. A bare cannula 4 is used withendoscopic graspers 3a. Another pair of laparoscopic graspers 3b isinserted into a cannula 4a which is inserted through a threaded gripper5. A third cannula 6, shown with a threaded outer surface, is providedfor an endoscope 34 which is inserted into the work space to provide thesurgeon with a video view of the graspers and body tissue.

The arrangement of the cannulas and trocars is required because theabdomen must be inflated to make room for the surgeon to work. The smalldiameter of the cannulas keeps the incisions small, and the matchingdiameter of the laparoscopic instruments is necessary to prevent leakageof the insufflation gas from the abdomen. Laparoscopic instruments ofvarious designs are available, and they generally are about 5 to 12 mmin diameter (to match the inside bore of the cannulas) and about 10 to40 cm in length. They are long and therefore difficult to use, and theyare usually used when the surgeon can see them only through thelaparoscope. Modern laparoscopic procedures require the surgeon to viewthe procedure on a video monitor. It may take a surgeon a lot ofpractice before becoming comfortable and skillful with the laparoscopicgraspers, grippers and scissors. These tools are more difficult to usethan the surgical tools which every surgeon uses in normal surgery, suchas those shown in FIG. 3, in use during open laparotomy. The normalgraspers are shown in use while the surgeon is tying off a suture. Thisnormal procedure is familiar to a large number of surgeons. The normalsurgical graspers 7a and 7b are shown in use in FIG. 3, suturing bodytissue 8 with suture 9, and it can readily be appreciated that thelaparoscopic graspers shown in FIG. 2 require significantly more skillthan the normal surgical tools. One of the drawbacks of the knowncannulas and grippers is that they are adapted to admit only relativelynarrow instruments, and are therefore generally unsuited for use withordinary open-incision surgical tools.

It would be advantageous to use normal surgical tools duringlaparoscopic procedures, but this is usually not permitted by thetypical construction of the trocars and cannulas which are too narrow,long and rigid to permit passage of the normal surgical tools. Mostsurgeons are very well trained in using conventional non-endoscopicinstruments, such as the open-incision graspers shown in FIG. 3, andnumerous procedures involving the graspers such as tying off a sutureare well known and well practiced. The endoscopic instruments shown inFIG. 2, on the other hand, are not well known and well practiced, andgenerally require significantly more skill than the more familiaropen-incision instruments. Thus, there is a need to provide cannulas andgrippers which would accommodate the instruments used in open-incisionprocedures.

SUMMARY OF THE INVENTION

In a typical endoscopic or laparoscopic operation, a surgeon creates aworking space inside the body through insufflation. To create theworking space for abdominal surgery, the surgeon makes a small incisionat, for example, the inferior margin of the umbilicus 1 as shown in FIG.1, and then uses his fingers or a dissecting tool such as a blunt nosedobturator to prepare a point of injection. The surgeon then inserts aVerres needle 2 into the abdominal cavity, and causes a pressurized gassuch as CO₂ to flow through the needle and into the abdominal cavity.This inflates the abdomen as shown in FIG. 1 and provides a workingspace for the surgeon. The needle may then be removed, and a cannula ortrocar/cannula combination may be inserted into the incision. Additionalincisions may also be made, and the first incision may be used to inserta laparoscope to assist in the placement of the other incisions. Theadditional incisions may each receive a cannula, and once severalcannulas are in place the surgeon can view the procedure, and/or insertlaparoscopic scissors, cutters, graspers or other tools through any ofthe cannulas.

As mentioned above, the trocars and cannulas can be used in endoscopicblood vessel surgery, laparoscopic cholecystectomy and laparoscopichernia repairs where a work space is created under the skin. In theblood vessel harvesting operation where the saphenous vein is to beremoved, a surgeon creates a tunnel between two small incisions over thesaphenous vein. Then a cannula and skin seal are inserted into eachincision. The tunnel is insufflated through one of the cannulas. Inthese procedures, the laparoscopic instruments are also inserted intothe working space through the cannulas, and the surgeon can watch thesurgery through a laparoscope inserted through the one of the cannulas.

The devices presented herein allow for use of normal surgical tools(such as the forceps and scissors used in open-incision surgery) inlaparoscopic procedures. The skin seal is fitted with one or moreballoons on the inner bore. These balloons can be inflated after theskin seal is inserted into the incision into the abdomen. Placement ofthe skin seal can be accomplished as usual, with the aid of a blunt orsharp trocar or cannula placed within the threaded skin seal. Thethreaded skin seal can be made of rigid plastic, as is customary, orpreferably it may be made of soft and pliable material such as latex orsilicone rubber. When the threaded skin seal is in place, the trocar maybe removed and the balloon may be inflated until it expands to fill theinner bore of the threaded skin seal, thus sealing the bore to maintainthe pressure created inside the abdomen with the insufflation gas. Theballoons are soft and pliable and can conform around the elements of theinstruments as they are moved about during use. Thus, normal orconventional surgical instruments may be passed between the balloons.Both normal surgical instruments and laparoscopic instruments may beinserted into the body through the balloons without disrupting the sealcreated by the balloons. The balloon is soft and pliable so that normalsurgical tools may be operated inside the inflated balloon segments andthe balloon segments will not hamper the operation of the tool to asignificant degree. The skin seal may be provided with a balloonmembrane that expands outside the lumen of the skin seal to create adumbbell, dog bone or bowtie shaped balloon which pinches the skin and,when necessary, fills the lumen of the skin seal.

More than one tool may be inserted through a single skin seal becausethe balloons are sufficiently pliable and may be inflated to a lesserdegree. In this manner, normal surgical instruments may be used inlaparoscopic procedures, taking advantage of the fact that they areeasier to use and more surgeons know how to use them, compared to thelong laparoscopic instruments. The balloon filled skin seal may be usedalso as a seal for laparoscopic incisions which are no longer necessaryor which the surgeon desires to plug temporarily while still leaving askin seal in place for later use.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external view of the abdomen of a patient undergoinginsufflation.

FIG. 2 is a cross section drawing of the insufflated abdomen of apatient with several trocars, cannulas and laparoscopic instruments inplace for a laparoscopic procedure.

FIG. 3 is a view of an open laparotomy procedure using normal surgicalforceps.

FIG. 4 is an exploded view of cannula with an inflatable balloon inside.

FIG. 5 is a cross sectional view of the cannula with the inflatableballoon inside.

FIGS. 6, 6a and 6b show cross sectional views of the cannula with theinflatable balloon shown in its inflated state.

FIGS. 7 through 7c show end views, from the proximal end, of the cannulawith inflatable balloon inside.

FIGS. 8 shows a pair of skin seals with the balloons inside, with normalsurgical instrument inserted through the balloons, deployed in themanner of intended use.

FIG. 9 shows a blunt obturator suited for use with the skin seal.

FIG. 10 shows a sharp trocar type obturator suited for use with the skinseal.

FIG. 11 shows the blunt obturator inserted in the skin seal.

FIGS. 12 and 12a show the skin seal with compressible packing.

DETAILED DESCRIPTION OF THE DRAWINGS

The cannulas and grippers described below allow for use of normalsurgical instruments in laparoscopic surgical procedures. The typicalgripper configuration is modified by adding a balloon or inflatablemembrane to the inner bore of the gripper and adding an inflation portto the wall of the gripper to allow for inflation of the balloon. Whenthe balloon is inflated, it closes off the inner bore of the gripper, sothat it provides an airtight seal during insufflation. The balloon ispliable so that tools can be inserted through the inner bore of theballoon and the balloon expands around the surgical tool to maintain theseal with little or no leakage of insufflation gas.

Referring to FIG. 4, the threaded skin seal 10 is made of a funnel ortube 11 with a generally conical or frustum outer shape with screwthreads 12 provided on the outer surface 13. The inner bore 14 isconical or funnel shaped, conforming generally to the shape of the outershape. Overall, the skin seal is funnel shaped, and the proximal end 15of the threaded skin seal has a large opening, and the distal or bottomend 16 has a smaller opening. The distal or bottom portion 16 of thethreaded skin seal may have a straight or cylindrical bore to provide atight fit with cannulas that have an outer diameter matching the innerdiameter of this straight bore. The distal or bottom portion of the skinseal may have a straight or cylindrical outer shape to make it easier toscrew the skin seal into an incision, and this straight section may bemade of variable length to match the different thickness of fat whichwill be encountered in different patients. The proximal end preferablyhas a conical inner bore to facilitate insertion of tools into theopening and through the cannula, but the inner bore may be straight. Theproximal end may also be described as flared, and may be graduallyflared in relation to the distal end, as though trumpet shaped, or maybe flared in a discrete fashion as in a typical funnel, with a straighttube at the distal end and a conical segment at the proximal end. Thescrew threads constitute a fastening means, and may be replaced withother fastening means such as a circumferentially ribbed outer contouror a longitudinally grooved outer contour. As shown, a flange 19 may beprovided on the proximal end of the cannula for ease in handling. Theflange 19 also provides a convenient means for mounting the bellows ontothe cannula. The skin seal is preferably 1 to 3 inches, or about 2 to 8centimeters, long.

A balloon membrane 20 has a generally conical or frustum shape matchingthe inner bore of the threaded skin seal and having the same overalllength of the threaded skin seal. The balloon membrane fits inside thethreaded skin seal and is sealed to the skin seal funnel at the upperedge and lower edge of the balloon membrane. The balloon membrane may beshorter than the skin seal, and may be sealed to the inner surface ofthe skin seal at points inside the skin seal, rather than at theimmediate distal and proximal edges of the skin seal. Also, the balloonmembrane may be longer than the skin seal and may be cuffed or foldedback around the outside of the skin seal at the proximal and distalends, and sealed at the cuffs.

An inflation port 21 is provided, comprising a hole in the wall 22 ofthe threaded skin seal. An inflation tube 23 or Luer fitting connectsthe inflation port to a suitable pump such as the syringe 24 shown inFIG. 5 or the squeeze pump 25 shown in FIG. 6. Where the syringe isused, the membrane may be inflated and deflated repeatedly by pushingand pulling on the syringe plunger 26, thus forcing air into the bladderand sucking air out of the bladder. A one-way valve or stopcock may beused to seal the membrane so that the pump or syringe may be detachedfrom the skin seal for more convenient use. Alternately, an inflationport can be provided at the distal tip of the skin seal, comprising anopen airway between the inflatable membrane and the insufflated workspace. In this manner, the insufflation gas enters the skin seal frominside the body to pressurize and inflate the inflatable membrane. Inthis manner, an automatic seal is created upon insertion of the skinseal into the insufflated space. This simplifies placement and use ofthe skin seal because there is no need for a separate syringe or pump toinflate the membrane.

In the preferred embodiment, the balloon membrane 20 is made ofbiocompatible elastomeric or elastic material such as latex, siliconerubber or any other suitable compliant material, elastic material orinflatable material. The cannula 10 is made of rigid or flexiblematerial, soft or hard plastic, high density or low densitypolyethylene, polypropylene, thick latex, silicone rubber or any othersuitable material including plastic, elastic or non-elasticbiocompatible material.

As shown in FIGS. 4 and 5, the inflatable skin seal may be constructedby applying an elastic cylindrical or conical balloon membrane 20 to theinner bore of skin seal cannula 10 and sealing the distal end of theballoon to the distal end of the cannula and sealing the proximal end ofthe balloon to the proximal end of the cannula, thereby creating aninflatable space between the cannula and the membrane. Alternatively, afully formed balloon bladder, comprising inner and outer conicalmembranes sealed to each other at their distal and proximal ends can beprovided and fixed to the inner bore of the cannula. The overall shapeof the balloon will be conical, funnel shaped or flared to match theshape of the inside of the skin seal. While one balloon is depicted ineach of the figures, two or more balloons may be used to guard againstthe possibility of rupture and loss of insufflation pressure during anoperation, or to facilitate manufacture, or to facilitate use of theskin seal with particular tools. A membrane seal may be provided at anycross sectional plane, within the skin seal, to guard against loss ofinsufflation pressure.

FIG. 6 shows the inflatable skin seal with the membrane in its inflatedcondition. The squeeze pump 25 is used to force air into the spacebetween the balloon membrane 20 and the wall of the cannula, causing themembrane to inflate within the cannula. The inflated membrane can beinflated until it completely obstructs the inner bore of the cannula andprovides an air-tight seal between the distal and proximal ends of thecannula. The cannula can be thin-walled and flexible enough to expand,as well, thereby further improving the seal between the cannula and theskin incision. As shown in FIG. 6a, the membrane need not extend for thefull length of the cannula, but may instead be sealed to the inner boreat various points inside the cannula. The cannula in FIG. 6a has aballoon 20 only in the conical inner bore of the proximal section of thecannula, and this facilitates use of graspers, scissors and other suchinstruments which might pinch the balloon when operated, orunnecessarily reduce the internal diameter of the narrowest portion ofthe cannula. As shown in FIG. 6b, the wall of the cannula may be madeflexible enough to expand outward when the skin seal is inflated, sothat any gaps or looseness in the seal between the outside of the skinseal and the skin incision are closed by the expansion of the outer wall22 of the skin seal.

FIG. 7 shows the view of the inflated membrane viewed from the proximalend of the cannula. The membrane naturally bulges in two or more radialsections or segments 27 to fill the lumen of the cannula. The expansionof the balloon sections need not be controlled, but may be controlled tofacilitate operation of graspers or other hinged and pinching tools. Forexample, the application of restrictors, comprised of thickened strips50 and 51 along the length of the membrane, shown in FIG. 7a, may beapplied to the membrane to inhibit expansion along the strip. Wirebands, plastic bands, or a line of adhesive gluing the balloon membraneto the skin seal may also be used to prevent expansion of the membranealong a longitudinal line of the membrane extending from the proximalend (or near the proximal end) to the distal end (or near the distalend) of the funnel. In this manner, a uniform expansion can be obtained,with the membrane expanding from the walls of cannula to meet along auniform plane. A pinching tool used in the cannula can be opened andclosed along the plane defined by the inflated balloons, and the balloonwill pliantly close upon the lumen but allow the pinching tool to openand close with less chance of pinching and cutting the balloon. As shownin FIG. 7b, the inflatable membrane 20 may be placed on the inner boreof the skin seal in an eccentric manner, covering only a portion of theinner wall of the skin seal. FIG. 7c shows the eccentric inflatablemembrane in its inflated state.

FIG. 8 shows the skin seals 28, 29 and 30 with the balloon membranesinflated. Skin seal 28 has the funnel shape described above. A pair ofnormal surgical scissors such as Metzenbaum scissors 31 is insertedthrough one skin seal 28 and a pair of normal surgical graspers 7(examples include Kelly clamps, Kelly placenta forceps, and Mayo clamps)is inserted through the skin seal cannula 29 to perform operationsbeyond the distal tip of the cannula. The skin seals are shown screwedinto incisions through skin 32 and subcutaneous fat 33, and they mayalso extend through the peritoneum or other tissue when appropriate tothe operation. An endoscope or laparoscope 34 which can be insertedthrough one skin seal to provide a view of the procedure is shown in thecentral skin seal 30. Because the balloon is pliable and conforms aroundany device within the skin seal, the graspers may be manipulated insidethe cannula without breaking the insufflation seal. As the graspers aremanipulated, the membrane conforms around graspers but yields to allowthe graspers to be open, closed, twisted, pushed and pulled within theskin seal without substantially degrading the seal created by themembrane. It should be noted that a perfectly airtight seal is notnecessary, and some leakage of insufflation gas or fluid is acceptable,so long as insufflation gas or fluid can be injected at a ratesufficient to make up for any loses. Where the cannula itself is made ofa soft pliant material such as latex rubber or silicone rubber, theforceps may be manipulated even further, and deformation of the skinseal 28 will permit a wider range of motion for the forceps. Skin seal28 is shown with a pair of conventional surgical scissors 31 or shearsdisposed through the skin seal. The scissors may be opened wide, asshown, and the distal or proximal end of the skin seal will yield andflare out to allow operation of the scissors through there full range ofmotion and opened through the full throw (the "throw" referring to thelength of arc 35 over which the graspers or scissors may be opened) ofscissors 31 or graspers, as illustrated by flared distal portion 36 ofskin seal 28.

It will be readily appreciated that such operation would not be possibleusing standard cannulas. The normal surgical tools are much easier touse than the long laparoscopic instruments shown in FIG. 2. Also, thetools can be much larger, and have much larger operating implements. Forexample, the cutting edges of scissors 31 are much longer that cuttingedges on laparoscopic scissors, and can cut much more quickly. A commonmethod of dissecting tissue with normal scissors is to pierce connectivetissue with the closed scissors and open the scissors, operating thescissors in backwards fashion, so that the dull outer edges of thescissors pull connective tissue apart. This can be done very quicklyusing the skin seals 29 and 30, as compared to slow and tedious snippingrequired when using long laparoscopic instruments.

Placement of the skin seals may be facilitated with special bluntobturators shown in FIGS. 9, 10 and 11. The blunt obturator 37 providessupport for the skin seal as it is pushed and screwed into the incision.The blunt obturator comprises a peg 38 with an outer contour whichmatches the inner bore of the skin seal, a handle 39 a finger gap 40,and a blunt tip 41. The tip may be blunt and rounded, or it may be sharpand pointed, as illustrated by the sharp pointed trocar type tip 42 inFIG. 10, in which case the sharp point 42 can puncture body tissue. Theobturator is placed inside the skin seal as shown in FIG. 11, and theassembly is screwed into the body as a unit. After the skin seal is inplace, the obturator is removed to allow insertion of other devices intothe skin seal. The finger gap 40 leaves some space for the surgeon topush against the flange of the skin seal while pulling the handle 39,thus avoiding the possibility that the skin seal will be pulled out ofthe body with the obturator. Because the obturator fits tightly insidethe skin seal to give it support during insertion, it may inadvertentlybecome sealed to the inside of the skin seal, especially if there is anyleakage of body fluids or water into the skin seal. Any excessive forcerequired to pull out the obturator could result in pulling the screwskin seal out of the skin incision. To prevent the need for suchexcessive force, the portion of the obturator which fits inside the skinseal may be provided with vacuum breakers in the form of scored lines orchannels 43, circumferential grooves 44, or a roughened surface, toprevent a vacuum from forming between the skin seal inflatable membrane.The scoring or roughening may take any form.

An alternative embodiment of the screw-type skin seal uses a resilientpacking in the lumen of the skin seal cannula. As shown in FIGS. 12 and12a, the lumen 14 of the skin seal 10 is filled with resilient orcompressible packing 45 made of a closed cell foam. The foam may have athin skin 46 characteristic of closed cell foams. Alternately, thepacking may be made of any resilient foam material and the skin 46 maybe replaced with a layer of plastic or elastic material. The packing mayalso be made of a gel, gel-filled membrane, or extemely soft rubber orother very low durometer material capable of elastically conformingaround the surgical instruments. The packing is formed to fit into theskin seal, and is preferably slightly oversized so that it is compressedwhen inserted and sealed to the inside of the skin seal cannula. Thepacking is provided with a narrow slit, or a closed slit 47 throughwhich surgical instruments may be inserted into the body. When surgicalinstruments are pushed through the slit in the packing, the packingresiliently conforms around the instrument to obtain an airtight sealaround the instrument. When inserted through a skin incision into aninsufflated work space in the body, the skin seal with resilient packingaccomplishes a substantially airtight seal of the incision, thusmaintaining insufflation while allowing use of normal open surgeryinstruments in the endoscopic procedure. As with the inflatable membraneembodiments, this embodiment may be used with the normal open surgerygraspers and scissors, as well as endoscopic and laparoscopicinstruments, during endoscopic surgery.

The skin seals described above can be used for any endoscopic orlaparoscopic surgery to permit use of normal surgical instruments i.e.,ordinary open-incision surgical instruments. While the skin sealsdescribed above are useful in procedures requiring insufflation, theymay also be used in other endoscopic or laparoscopic procedures. The useof the skin seal in any endoscopic or laparoscopic procedures will allowdeployment of normal surgical tools while protecting the area of theincision from trauma caused by the operation of the surgicalinstruments. Where insufflation or flushing is required, the bladder inthe skin seal may be inflated to prevent undesired flow out of thecannula. Also, although the skin seal described above has been describedin the best known embodiments, fabricated with suitable materials to theinventors, the particular materials and shapes depicted in theillustrations may be altered and improved upon without departing fromthe inventions as claimed. It is specifically contemplated that thematerials be improved upon. Furthermore, although the devices have beendescribed in relationship to surgery requiring insufflation andendoscopic or laparoscopic surgery, the claimed devices and methods maybe used in surgical and non-surgical applications wherever the featuresof these device and methods prove beneficial.

We claim:
 1. A skin seal for use with laparoscopic trocars, laparoscopicinstruments and normal surgical instruments, comprising:a flexiblecannula shaped like a funnel, with a large open end referred to as theproximal end and a small open end referred to as the distal end, saidcannula having an outer surface and an inner bore defining a lumenpassing through the cannula; and at least one inflatable membranesecured to the inner bore of the cannula at its proximal and distal endsin such a manner that, upon inflation, the inflatable membrane expandstoward the center of the lumen of the cannula, said inflatable membranein its uninflated state contracting away from the center of the lumen toallow passage of an instrument through the lumen.
 2. A skin seal havingan inflatable membrane inside, said skin seal comprising:a flexiblecannula having a proximal end and a distal end, said proximal end havinga larger outer diameter than said distal end, said cannula having anouter surface and inner bore; and an inflatable membrane disposed withinthe inner bore of the cannula, said inflatable membrane having a conicalshape and having a proximal end and a distal end and a circumferencewhich becomes smaller from the proximal end to the distal end, saidinflatable membrane sealed around its circumference to the inner bore ofthe cannula in at least two longitudinal positions adjacent the proximaland distal ends of the cannula.
 3. The skin seal of claim 1 or 2 whereinsaid flexible cannula is made of elastomeric material.
 4. The skin sealof claim 1 or 2 wherein said flexible cannula is made of thermoplasticelastomer.
 5. The skin seal of claim 1 or 2 wherein said flexiblecannula is made of rubber elastomer.
 6. The skin seal of claim 1 or 2wherein said flexible cannula is made of rubber.
 7. The skin seal ofclaim 1 or 2 further comprising screw threads on said outer surface ofsaid cannula.
 8. The skin seal of claim 1 or 2 further comprisingfastening means on said cannula to fasten said cannula to the skin. 9.The skin seal of claim 1 or 2 further comprising a flange on saidproximal end of said cannula.
 10. The skin seal of claim 1 or 2 furthercomprising an inflation passageway in a wall of said cannula, saidinflation passageway communicating with said inflatable membrane.
 11. Asurgical access device comprising:a flexible funnel having a largeproximal end, a small distal end, an outer surface, and an inner bore;screw threads on said outer surface; a funnel shaped inflatable membranesecured to said inner bore of said funnel to form an airtight chamberbetween said inner bore of said flexible funnel and said inflatablemembrane; and an inflation port communicating with said airtightchamber.
 12. The surgical access device of claim 11 wherein saidflexible funnel is made of an elastomeric material.
 13. The surgicalaccess device of claim 11 wherein said flexible funnel is made of anonelastic material.
 14. The surgical access device of claim 11 whereinsaid inflatable membrane is disposed only within said proximal end ofsaid flexible funnel.
 15. The surgical access device of claim 11 furthercomprising a flange on said proximal end of said flexible funnel. 16.The surgical access device of claim 11 further comprising an inflationpassageway in a wall of said flexible funnel, said inflation passagewaycommunicating with said airtight chamber and said inflation port.
 17. Askin seal having an inflatable membrane inside, said skin sealcomprising:a cannula having a proximal end and a distal end, saidproximal end having a larger outer diameter than the distal end, saidcannula having an inner bore; an inflatable membrane secured to theinner bore of the cannula, said inflatable membrane having a conicalshape and having a proximal end having a larger diameter than a distalend, said inflatable membrane being disposed within the cannula with theproximal end of the inflatable membrane aligned with the proximal end ofthe cannula, and the distal end of the inflatable membrane aligned withthe distal end of the cannula, said inflatable membrane sealed to thecannula to create an airtight chamber defined by the inflatable membraneand the cannula; and an inflation port communicating with the airtightchamber.
 18. A skin seal comprising:a flexible tube having a proximalend, a distal end, and an inner bore, said proximal end having a largerouter diameter than said distal end; an inflatable membrane secured tosaid inner bore of said flexible tube, said inflatable membrane having aproximal end of larger diameter than said distal end, said inflatablemembrane being disposed within said tube with said proximal end of saidinflatable membrane aligned with said proximal end of said tube and saiddistal end of said inflatable membrane aligned with said distal end ofsaid tube, said inflatable membrane sealed to said tube; and aninflation port communicating with said inflatable membrane.
 19. The skinseal of claim 18 further comprising screw threads on an outer surface ofsaid flexible tube.
 20. The skin seal of claim 18 wherein said flexibletube is made of an elastomeric material.
 21. The skin seal of claim 18wherein said flexible tube is made of a nonelastic material.
 22. Theskin seal of claim 18 further comprising a flange on said proximal endof said flexible tube.
 23. The skin seal of claim 18 further comprisingan inflation passageway in a wall of said flexible tube, said inflationpassageway communicating with said inflatable membrane and saidinflation port.
 24. A skin seal having an inflatable membrane inside,said skin seal comprising:a cannula having a proximal end and a distalend, said proximal end being flared in relation to the distal end andhaving a larger outer diameter than the distal end, said cannula havingan inner bore; an inflatable membrane secured to the inner bore of thecannula, said inflatable membrane having a conical shape and having aproximal end having a larger diameter than a distal end, said inflatablemembrane being disposed within the cannula with the proximal end of theinflatable membrane aligned with the proximal end of the cannula, andthe distal end of the inflatable membrane aligned with the distal end ofthe cannula, said inflatable membrane sealed to the cannula to create anairtight chamber defined by the inflatable membrane and the cannula; andan inflation port communicating with the airtight chamber.
 25. Asurgical access device comprising:a flexible tube having a proximal endand a distal end, said proximal end having a larger diameter than saiddistal end, said tube having an outer surface and an inner bore; aninflatable membrane disposed within said inner bore of said flexibletube, said inflatable membrane having a conical shape and having aproximal end and a distal end, said inflatable membrane being sealed tosaid tube adjacent the proximal and distal ends of said tube; and aninflation port communicating with said inflatable membrane.
 26. Thesurgical access device of claim 25 further comprising screw threads onsaid outer surface of said flexible tube.
 27. The surgical access deviceof claim 25 wherein said flexible tube is made of an elastomericmaterial.
 28. The surgical access device of claim 25 wherein saidflexible tube is made of a nonelastic material.
 29. The surgical accessdevice of claim 25 further comprising a flange on said proximal end ofsaid flexible tube.
 30. A device for sealing an opening through the skininto an insufflated space within the body, said device comprising:aflexible funnel having proximal and distal ends; and an inflatablemembrane disposed within the funnel and sealed to the funnel adjacentits proximal and distal ends, said inflatable membrane being sized anddimensioned to fill said flexible funnel when inflated and to leave anopen lumen through said flexible funnel when deflated.